I spent most of last night trying to manually config the WIFI to automatically connect to my University's WPA2 Enterprise network using the RP2 w/ the Edimax EW-7811Un. I finally got the wpa_supplicant to behave correctly with all the correct credentials and it turns on automatically on boot, but I'm having some strange issues with RX packet loss. For example when I ping some server like google, the packets take forever to send. Mind you the ping time is very quick around 20ms or so but the time it takes to either send the request or receive the packet back is very long. When I do an ifconfig the only strange thing I see is (on wlan0)

RX packets:198 errors:0 dropped:152 overruns:0 frame:0

The dropped packets are where I think I'm getting the huge latency. (There are no dropped packets on the TX side btw) Now normally you would think this is a network problem but I'm on my laptop on the same network and I'm getting no packet loss at all. Does anyone have an idea of what is going on here? Running iwconfig the quality reports

Link Quality=100/100 Signal Level=70/100 Noise Level=0/100

Could the signal level have anything to do with it? I can't imagine it's causing a 76% packet loss, right?

  • Is your RPi the client, or are you using it as a router/firewall to connect other devices behind the RPi? Are you noticing any difference in the packet loss between internal (LAN) and external (Internet) targets? – bobstro Sep 8 '15 at 17:12
  • @bobstro I'm using the Pi as a client. The only time I'm connecting to it is if I want to ssh into it. I can do that but it's slow as well. If that's what you mean by LAN (connecting to devices through the same router), then it's still slow. If you mean LAN as in connecting to the router through a wired connection, I have no access to that. There is no cat5e LAN socket in my room (that I see at least haha)... – kaldi Sep 8 '15 at 17:48
  • So from your computer to RPi via wifi is also slow, correct? I've used that same wifi adapter on older RPis with no issues, but there is the possibility that your power supply could be weak. Do you notice a rainbow square at top-right of your display? Do you see the loss when you do a simple ping between your computer and RPi? – bobstro Sep 8 '15 at 18:19
  • @bobstro It might be important to point out that on my home network using a WRT router the the raspberry pi has no packet loss or noticeable latency when using SSH, so I think we can rule out the wireless adapter malfunctioning at least on a hardware level. Also I do not see a rainbow square at the top right of my desktop. So anyways, when I go to ping the device I get very little packet loss if none at all, at least from what the ping command shows, although I do notice that the ping times are very inconsistent, ranging from 3ms to 250ms, which is strange. Any other tests you might recommend? – kaldi Sep 8 '15 at 19:15
  • Try pinging local and Internet IPs with varying packet sizes. (e.g. ping -s 1024 Do you get loss at smaller and larger packet sizes, particularly at 1.5K size, or at all sizes? Varying timing that much is odd, although wifi is subject to a lot of factors. – bobstro Sep 8 '15 at 20:05

Your Answer

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Browse other questions tagged or ask your own question.